EF0 tornado, (Eyw)Key West Inl Ar, Florida, December 18, 2009

1. EF065 to 85 mphthis tornado

   Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

2. EF186 to 110 mph

   Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

3. EF2111 to 135 mph

   Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

4. EF3136 to 165 mph

   Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

5. EF4166 to 200 mph

   Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

6. EF5over 200 mph

   Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

7. Unrated

   The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

Rating

EF0

Date

December 18, 2009

Touchdown

2:35 PM EST (19:35 UTC)

Lifted

2:40 PM EST (19:40 UTC)

On the ground

5 minutes

Path length

1.2 miles (1.9 km)

Path width

25 yards (23 m)

Deaths

0

Injuries

0

Property damage

$10,000

County

Monroe County

Touchdown point

24.553, -81.749

Lift-off point

24.569, -81.740

Record number

0912181335-01

A supercell thunderstorm tracked northeast along the Florida Keys. The thunderstorm first produced a weak tornado at the extreme southeast tip of Key West and south Stock Island, then tracked northeast just north of Big Pine Key before crossing the Upper Florida Keys from the west-southwest at Key Largo. A second weak tornado was reported at several Florida Bay shoreline properties.

A weak tornado produced EF0 damage across the extreme southeast part of Key West through south Stock Island. The tornado was first observed by a motorist just offshore South Roosevelt Boulevard before moving briefly onshore at a hotel. Over a half dozen palm trees with some decay were snapped at the base. Lawn furniture associated with the hotel's tiki hut north of the tornado path were blown southeast onto South Roosevelt Boulevard in the torando's wake. The tornado tracked northeast across Cow Key Channel before moving ashore south Stock Island along 12th Avenue. Two trees were downed onto 12th Avenue in a northeast direction. A deck umbrella was lofted northeast from the east end of 11th Avenue onto power lines on 5th Street, bringing down the lines and causing a power outage throughout the area. The tornado continued northeast and likely lifted or dissipated over 5th Avenue northeast of Bernstein Park. There, a small ornamental tree was found snapped at the base and laying toward the west partially onto 5th Street. Several trash cans placed around Bernstein park had fallen and rolled southward or southeastward. At the tornado path northeast terminus, a television cable line was downed. Maximum winds were estimated at 60 to 70 mph along the path from Key West through 11th Avenue in Stock Island.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.

Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.

The Storm Prediction Center had this point in a Slight Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 16:30 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.

The Key West radar (KBYX), 6 km away, was scanning. The volume nearest the touchdown began at 19:36 UTC.

Open the radar archive at this moment, over the track

Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.

Local storm reports within 60 km of the path, in the three hours either side.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

The live radar over the trackEvery 2009 tornado in FloridaEvery tornado in Florida since 1950Warnings in force in Florida nowThe forecast where you are

3 more were confirmed in the United States that day.

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.